Lamp-socket.



A. c. MCWILLIAMS.

LAMP SOCKET.

APPLICATION FILEDMN. 12. |914.

1,167,579. 1 Patented Jan.'11,1916.

. V 2 SHEETS-SHEEH @SQ/97,4 Lal A. C. MCWLLIAMS.

LAMP SOCKET.

APPLICATION FILED MN. 12, 1914. v 1,167,579. Patented Jan.11, 1916.

2 SHEETS-SHEET 2.-

.ARTHUR C. MGWILLIAMS, F SOUTH. BEND, INDIANA.

LAMB-SOCKET. i

Specification of Letters Patent.

Application filed vJanuary 12, 1914. I seriai No. 811,663.

To all whom t may concern:

Be it known that I, ARTHUR C. MGW'IL- LTAMs, a citizen of the United States, residing at South Bend, in the county of St.

Joseph and State of Indiana, haveinvented a certain newv and useful Improvement in Lamp-Sockets, of which thefollowingI is a specification.

My invention relates to lamp sockets, especially of the type used for street lighting.

In lighting streets or other'outdoor places by incandescent lamps it is usual to connect a number of lamps in series and .in such case it is necessary yto provide means whereby, when a filament of any one of the lamps is burned out or broken and the circuit thus interrupted, the circuit will be automatically restablished by devices. located in the lamp.

socket and capable of shunting the lamp circuit when it breaks. circuiting ofbroken lampfilaments has been accomplished by so called film sockets in which two terminals, normally insulated by an interposed film of insulating material. are arranged in multiple with the principal terminals of the socket, so that the instant increase of voltage (which results from full' line voltage being impressed upon the oc" currence of the break) burns out or punc- `tures the lm and closes the circuit throughthe two adjacent terminals thus providing a new path for the'current. A short circuiting spring contact is also provided and so arranged in the socket as to afford a path for the current when the lamp is absent. But the film sockets heretofore employed have had disadvantageous characteristics which it is my .purpose to eliminate.

With this general object in view it is my purpose to provide a film socket -Which, practically speaking, cannot be misoperated; also to provide a socket which .is simple, lsafe against short circuits and leakage currents, weather proof, durable, attractive in appearance and cheap to manufacture.

More specifically my objectsare first, to provide convenient means for replacing burned out lms, second to render this possible without danger of having them damaged in the process, third to provide means for securely holding the film and preventing it from creeping as a result of the stresses exerted upon the parts by the laction of the wind, fourth to provide a construction such that there shall be no exposed live metal parts on the back of the socket, fifth to pro- The shunting or shortvide a construction in' which the vparts are so securely held together that the action of Patented Jan.' 11, 191e.

the Wind'cannot work any of the parts loose and permit the lamp to drop.

In one type of known socket it is necessary to always have the lamplin the socket when receiving the part' containing the fila-v ment, otherwise the film will become punctured.

One of my objects is to provide a construction such that the lamp alone may be removed or the film holder and the lamp together may be removed without opening the line or puncturing the film.

Another object is to provide means for compressing the film vin such manner that it will always operate at practically the same puncture voltage.

It is also an object to provide a construction adapted to utilize circular or ring type f filaments which on account of the exposed area give a liberal puncture surface.

It isl also an object to provide a removable film holder such that the operating electrician may, if pressed for time or operating under adverse weather conditions, supply himself with a number of film holders containing fresh fllms. Then when he comes to a broken lamp he may simply remove lthe old film holder and substitute a new one containing a fresh film; replacing the burned out film in the old holder at his leisure after returning to the central station.

These several characteristics are not all individually new, but some of them are new in themselves, and furthermore, so far as I am aware, my device is the first to combine them all in a single structure.

I accomplish my objects by the mechanism illustrated intheeac'companyi'ng draw-o ings in which- Figure l is an axial section on the line '1-1, Fig. 3. ,Fig -2 is similar to Fig. 1 but shows the film holder and lamp removed from the base. looking` `directly thereinto. tional viewon the line 4 4, Fig. 3. Fig. 5 is a rear viewof'the-base. Fig. 6 is a face view of the parts in which the film is contained. Fig., 7 is a vertical section on the irregular line 7i-7 Fig. 8. Thisline of section isselected to more clearly illustrate the relation of the binding posts and other parts of the base. Fig. 8 is a bottom view of the stationary parts of'Fig. 7. Fig. l) is a per.

spective on an increased scale ofthe lmetal- Fig. 3 is a view of the 'base Fig. 4 is a seclic ring which holds the film between itself and the inner film holding shell. Fig. 1U

is a perspective of the upper end of the internal shell with the insulating ring in position. Figs. 11 and 12 are face and edge views respectively of the dielectric, destructible films. Fig. 13 is a central section of the shoe against-which the film holder abuts.

Similar numerals refer to similar parts throughout the several views.

The base 1 is formed 'of porcelain or other insulating material and is designed to be attached to a suitable stationary support. Within this base is located a metallic shell 2 which has screw-threads formed therein and is permanently connected to one of the -binding terminals. In the present design the connection is by means of a screw 3 connected to a strip 4 connected to a terminal post 5 having a binding screw 6. The parts, 3, 4, 5 and 6 are vembedded in the base, the strip 4 being overlaid by insulating compound 7 as best shown in Fig. 4. An extra screw 8 is desirable for assisting the screw 3 to hold the shell 2 securely in position. This screw is held at the back of the base by a nut 9` overlaid by insulating compound 10. The opposite binding terminal consists of the parts 11, 12 and 13 similar in construction and function to the part 4, 5 and 6 respectively. The strip 11 is overlaid by insulating compound 11a as best shown in Figs. 1 and 2 and is electrically connected to thespring contact 13a vand shoe 14 by a screw'15. The part 13a constitutes a short circuiting switch and normally tends to engage the inner end of shell 2 as shown in Fig. 2. Said switch is operated by a post 16 which is centrally located and formed of conductive material. Shoe 14 is also of metal and has a flange .142L (see Fig. 13) which is annular and makes electrical contactrwith the Elm holder when the latter is screwed home into the shell 2. AIt also acts as a stop to limit the distance to which the film holder may be inserted.

The lnr holder comprises the metallic shell 17., the annular metallic plate 18 and the insulating ring 19. Shell17 has external and internal threads, the external threads enabling it to screw into the shell 2 and the internal threads enabling itto receive the base 20 of the lamp. Said Shelli 17 is provided with a collar 21 of insulatin material which affords means whereby the shell may be manipulated. Plate 18, which l is shown separately on an increased scale in Fig. 9, overlies the film 22 and holds the film between itself and the inwardly fianged end of the shell 17. In the preferred desi plate 18 is provided with fingers 18a whlcli enter notches 19 in the ring 19. These fingers snap over said ring and hold the plate in position. The notches preventthe plate from rotating and damaging the film when the film holder is being screwed rmly up against the shoe 14.

In operation when the lamp is absent, the spring switch 13l will engage the inner end of the external shell 2 as shown in Fig. 2 and will thus form a direct path for the current from one of the main binding terminals to the other. W'hen the electrician is ready to install a lamp he provides himself with a film holder containing a film which is intact and screws said holder into the external shell until the plate 18 is in firm electrical contact with the flange 142t of shoe 14. This puts plate 18 into electrical contact with terminal post 12 but the lm 22 insulates said ring from shell 17 of the film holder. The electrician then screws the lamp into the internal shell, the end of the lamp base engaging the post 16 and forcing switch 13a back out of contact with the external shell. As soon as the switch 13L has left the external shell (see Fig. 1), the path through said switch will be broken and the current will pass from said switch through post 16 to the center terminal 22 at the end of the lamp base, thence through the lamp filament 23 to the lamp shell or collar, thence through the internal shell 17 and external shell 2 to the terminal post 5. If now the lamp filament becomes broken,

the impressed voltage will cause the penetration or destruction ofthe film 22 and permit the current to pass directly from the shoe 14 andv plate 18 to the inner end of the internal shell 17, thence through the externalshell 2 to the terminal.

It will be noted that with my construction the film is carried by a holder which is removable as a whole. In consequence after a lm has been burned out it is unnecessary for the electrician to immediately place a new one in the holder. By supplying himself with a number of holders provided with intact films, all he has to do is to replace the holder having a Vburned out film with .a holder havingl a fresh film. This enables him to replace the burned out film at his leisure and'avoids the necessity of working in the, dark or under adverse weather conditions or when time for making the rounds is limited. Furthermore with my construction the lm holder has no effect upon the switch 13a and therefore may be inserted or withdrawn without disturbing it. Again, the electrician may screw the lamp into the film holder either before or after the film metallic shell mounted on said base and electrioally connected tovone of said terminals, a film holder comprising a metallic shell screwing into the first mentioned shell and being internally threaded to receive the lamp, said internal shell having a fiange formed at its inner end, an annular metallic plateforming part of said film holder and lying adjacent to the flange of the internal shell, a film normally insulating said plate from the flange of the internal shell, means composed of insulating material for securing said plate to said internal shell, means for electrically connecting said plate to the opposite main terminal when the film holder is in position in the external shell, and means for electrically connecting the center contact of the lamp with the last mentioned terminal.

2. A lamp socket comprising an insulating base provided with two main terminals, a metallic shell inclosed within said base and permanently secured to one of said terminals, a dielectric film, a, film holder comprising an annular metallic plate, a metallic shell screwing into the first mentioned shell and having an internal screw thread for receiving the lamp, said internal shell having an annular fiange at the inner end substantially co-eXtensive with said plate and separated therefrom by said film, said film holder also including a ring of insulating material for holding the internal shell and film and annular plate assembled, means for electrically connecting said plate to the opposite main terminal of the device, and means for electrically connecting the center contact of the lamp to the last mentioned terminal.

3. A lamp socket comprising an insulating base provided with two main terminals, a metallic shell inclosed within said base and permanently secured to one of saidl terminals, a dielectric film, a film holder comprising an annular metallic plate, a metallic shell screwing into the first mentioned shell and having an internal screw thread for receiving the lamp, said internal shell having an annular flange at the inner end substantially co-extensive with said plate and separated therefrom by said film, said film holder also including a ring of insulating material for holding the internal shell and film and annular plate assembled, means for electrically connecting said plate to the opposite main terminal of the device, and a switch electrically connected to the last mentioned terminal, said switch being engaged by they center contact of the lamp and tending to for receiving the base of the lamp, said film holder comprising a metallic shell having formed thereon an annular flange approximately co-eXtensive with said film, an insulating collar whereby said shell may be manipulated, an annular plate substantially co-eXtensive with said film and separated by said film from the annular flange on the internal shell, an insulating ring fitting over the inner edge of flange on said internal shell, said plate having spring fingers adapted to snap over said insulating -ring for holding the plate in position, and means for electrically connecting said plate to the opposite terminal when the film holder is in position within the first mentioned shell.

5. In a film socket, the combination of an insulating base, two main terminals on said base, a metallic shell located within said base and electrically connected to one of said terminals, an internal metallic shell screwing into the first mentioned shell and having internal screw threads for receiving the base of the lamp, said internal shell having an annular flange at its inner end, an annular film supported upon the flange on the internal shell, an annular plate overlying said film, means for removably holding said plate upon said film, an annular shoe electrically connected to the opposite terminal on the base and located in position to be engaged by said plate when the parts are assembled, ay post contact electrically connected to the same terminal as the shoe and adapted to pass through the central opening of the shoe, film, film holding plate and internal shell to energize the center contact of the; lamp, and a spring switch electrically connesses.

ARTHUR C. MCWILLIAMS. Witnesses:

GrLnRT T. DUNKLIN, J. F. CHADBOURNE. 

